Abstract
The article presents the results of studies of the growth and development of purebred and crossbred lambs of the Kazakh fat-tailed coarse-wooled breed. The live weight of purebred and crossbred Kazakh fat-tailed coarse-wooled lambs at birth and during the growing period was at a satisfactory level. The live weight of the experimental purebred and crossbred lambs of the Kazakh fat-tailed coarse-wooled breed at birth was in the range of 4.1-4.5 kg, on the 20th, 60-120th day respectively, 8.2-9.1, 16.8-17.9 and 31.5-34.4 kg. The average milk yield of purebred ewes was 25.85 kg, of crossbreeds – 27.5 kg. The average daily gain in live weight of purebred lambs for 60 days was 211.7-245.2 g and 223.3-275.0 g, that is, the difference was observed within 33.5 and 51.7 g or 15.8-23.1 %. In addition, the article calculates and presents measurements and physique indices of lambs at birth and at the age of 4.5 months.